Early man preferred to stay at home in a comfy cave than to roam, scientists have learned.

Women, on the other hand, liked to get around two million years ago.

The evidence comes from two cave sites in South Africa where adjacent communities of now extinct humans once lived.

Analysis of their teeth showed whether or not individuals were local or had arrived from another area.

More than half the female teeth were from outside the region, compared to about 10% of the male teeth, an international team of researchers found.

The experts concluded that most males lived and died in their birth places, while females were more likely to find new homes.

"One of our goals was to try to find something out about early hominid landscape use," said lead researcher Professor Sandi Copeland, from the University of Colorado at Boulder, US.

"Here we have the first direct glimpse of the geographic movements of early hominids, and it appears the females preferentially moved away from their residential groups."

The two populations were from different early human species. One, Australopithecus africanus, may have been a direct ancestor of modern humans. The other, Paranthropus robustus, belonged to a "dead end" branch of the human evolutionary tree.

They occupied the adjacent Sterkfontein and Swartkrans cave systems at different times between around 1.7 and 2.7 million years ago.

The scientists used a laser technique to test 19 teeth and identify dietary signatures locked within their enamel.

Differences in tiny traces of the element strontium eaten with vegetation indicated where the owners of the teeth grew up.

The results, reported in the journal Nature, were surprising, said Prof Copeland.

"We assumed more of the hominids would be from non-local areas since it is generally thought the evolution of bipedalism (walking on two feet) was due in part to allow individuals to range longer distances," she said.

"Such small home ranges could imply that bipedalism evolved for other reasons."

The female dispersal pattern was similar to that of modern chimpanzees and bonobos, as well as some human groups.

But it was unlike that of most other primates, including gorillas, whose females stay with the group they are born in until the males move elsewhere.

It is not clear where the roving females identified in the study spent their formative years.

Why the males preferred to stay at home is also uncertain. One possibility is that they were simply reluctant to leave their caves.

"I've never thought of these early male hominids as the quintessential cavemen, but the potential use of caves at this early time period is something worth considering," said co-author Professor Matt Sponheimer, also from the University of Colorado.